The fabrication of integrated circuits includes many diverse processing steps. One of the operations frequently employed is the deposition of a dielectric film into a gap between features patterned over or into a silicon substrate. One method of depositing such a film is through plasma enhanced atomic layer deposition (PEALD). In this type of method, several operations are undertaken in a cyclic manner to deposit a conformal film. Typically, PEALD processes include the steps of (a) providing a dose of a first reactant to a reaction chamber, (b) igniting plasma in the reaction chamber (c) purging the reaction chamber, (c) providing a flow of a second reactant, (d) igniting plasma in the reaction chamber, and (e) extinguishing the plasma and purging the reaction chamber. A single cycle of a PEALD process deposits a monolayer of material. In PEALD, any number of reactants is deposited and any number of purging operations takes place to reach a desired film thickness.
A large number of PEALD processes result in deposition of the dielectric film that has a non-uniform thickness across a surface of silicon substrate. It is in this context that embodiments described in the present disclosure arise.